20201989 Ver 1_Draft MP Comment Memo_20230404

DEPARTMENT OF THE ARMY
WILMINGTON DISTRICT, CORPS OF ENGINEERS
69 DARLINGTON AVENUE
WILMINGTON, NORTH CAROLINA28403-1343
REPLY TO
ATTENTION OP:
April 4, 2023
CESAW-RGM/Isenhour
MEMORANDUM FOR RECORD
SUBJECT: Wildlands Cape Fear 06 Umbrella Mitigation Banking Instrument and East Mingo
Creek Mitigation Site Draft Plan Review, Johnston County, NC
PURPOSE: The comments listed below were received from the NCIRT during the 30-day
comment period in accordance with Section 332.8(d)(7) of the 2008 Mitigation Rule.
USACE AID#: SAW-2020-02093 NCDWR# 20201989
30-Day Comment Deadline: January 16, 2023
Kim Isenhour, USACE:
1. Have adjacent landowner concerns regarding hydrologic trespass on her pasture been
resolved?
2. Figure 11:
a. Please add a flow gauge to Wolf Creek. With the amount of sediment coming into
the system, there's a concern that maintaining a defined channel may be
challenging.
b. Please add a cross-section to Beaver Creek restoration area.
c. Please add a cross-section to the restoration portion of Deer Creek.
d. I'm confused why the erosional channels are shown on this figure. These should
be re -labeled that they will be filled, or removed from the figure.
e. Please add a veg plot to the ponded area adjacent to Wolf Creek.
f. Please capture the areas where the erosional channels are being filled with a
random veg plot at least once during monitoring.
g. Please add a photo point to crossing #2.
h. Please plan for a random veg plot along Beaver Creek at least once during
monitoring.
i. Is there a rain gauge on site?
j. Please include photo points at all crossings.
k. Please update Table 19 with these additions.
3. Page 6: Did you discuss thinning any of the loblolly pines along Cow Creek? Is there a
concern that these will provide a seed source? Do you plan to use the mowing
guidelines during monitoring to prevent pines from overtaking the floodplain?
4. Will pasture grasses be treated prior to planting?
5. Page 13, Section 3.5: After discussions with WRC, we have concerns with proposed
ford crossings in a sand -bed system. Depending on the underlying material, it can be

very difficult to maintain a stable crossing. WRC will not object if you feel like the
geology and construction design will maintain a stable crossing while allowing the sand
bed system to transport bedload naturally while maintaining surface flow. Please
provide photo documentation of each crossing annually.
6. Section 3.5: Are there encroachment concerns from the housing development west of
Rabbit Creek? Additional signage and horse tape may be beneficial to establish a
boundary.
7. Section 3.3.4: It would be helpful for the review if a summary table of existing
groundwater gauge data was included.
8. Table 6: Are the impacts for crossings included in this table?
9. It would be helpful to include the WETS table information for normal conditions.
10. Section 4.2 and Appendix 4: Have you looked up the site on iPaC recently? The
regulatory viewer shows the Tricolored bat, RCW and Monarch Butterfly for that area. I
was glad to see several pollinator species in the seed mix.
11. The DWQ stream ID form for Wolf Creek lists invasive aquatic plants. Which invasive
aquatic species are on the site?
12. Is there potential for adaptive management needs on Snake Trib if the pond upstream is
fixed and flow from the pond changes? This was an IRT concern during the site visit so
it may be helpful to include this discussion in the AMP section.
13.Appendix 5: It might be beneficial to add discussion on crossing maintenance if any is
anticipated.
14. Appendix 6: 1 know this is template language, but please add item #7 for the initial
credit release that includes documentation of the establishment of the long-
term /endowment/esc row account.
15.Appendix 8: The cost calculation from UP2S may need to be updated. The mitigation
plan lists 45.89 acres, but the acceptance letter and spreadsheet from UP2S list 44.75
acres. They may need to update their estimates based on inflation and the mileage
costs as well.
16. Please confirm that the BM at the top of Beaver Creek is not located within a
jurisdictional area. I couldn't locate the BMP on the design sheets to verify it's location.
17.Appendix 1: The growing season listed on the gauge data is March 1 to November 16.
Table 10 on page19 lists the growing season as March 17 to November 5. Please
update the final mitigation plan with the proposed modified growing season start and
end dates and include photo documentation of multiple species bud burst in Appendix 1
to support the proposed March 1st monitoring start date.
18. Page 28 and Table 18: For the ponded areas, the proposed 160 stems per acre of
planted trees is not sufficient. You will need to propose interim performance standards
for monitoring years three and five (this applies to the discussion on page 28). You will
also need to propose a performance standard that addresses stem density for shrub
species. An acceptable performance standard example would be, "Trees will have 160
planted stems per acre at MY07, survival of at least 245 planted stems at MY-3 and 200
stems per acre at MY-5. Shrubs will have 160 surviving plants at MY-3, 130 at MY-5
and 105 at MY-7. Herbaceous coverage should be at least 80% at MY-7. "
19. Page 30, Section 6.9: Are the ponds west of Cow Creek and Snake Creek stable? Is
there a concern of the dams breaching?
20. Is there a sediment source in the field west of Wolf Creek?

21. Page 33: The summary credit table lists a 2% benthic credit adjustment. I don't recall
benthic monitoring being discussed in the text except for one line on page 35. 1 also
don't see monitoring locations on Figure 11. The Guidance states that for those projects
where this monitoring is conducted, an additional credit of up to 2% may be generated
for each reach being monitored, it would not be based on the entire site unless all
tributaries were being monitored. Please clarify and adjust accordingly.
22. Section 9.0, page 35: The vegetation plots proposed on Figure 11 appear to be
adequate to monitor the overall veg success of the site, except for adding a plot
adjacent to Wolf Creek. I don't think it's necessary to adjust the number of vegetation
plots.
23. Page 37, Table 20: Since the crossings are internal, crossing maintenance should be
discussed in this section.
24. Design Sheets: Grading and limits of disturbance lines were not included. Given the
extent of wetland restoration, ditch filling and stream restoration through existing
wetlands, it would have been helpful to see preliminary grading information.
25. Design Sheets — Please confirm that stream reach credits are ending at the confluence
streambank and not the confluence centerline.
26. The narrative discussed the existing wooded areas onsite as having a mature canopy
but lacking an understory, as well as the need for privet control. Why was supplemental
planting with understory and shrub species not proposed across the site? For my
educational purposes, what is the stem survival of understory plantings in your
experience?
Travis Wilson, NC WRC:
The draft mitigation plan does not provide any design detail of the two stream crossings.
Agency review of the draft mitigation plan provides the opportunity to review and comment on
the design. DMP comments allow agencies and the provider to discuss those comments for
incorporation in the final mitigation plan. The final mitigation plan should not be providing new
information but should be to assure all agreed recommendations are incorporated. Crossing
designs are an integral component to assuring stream stability and Aquatic Organism
Passage. The details of the crossings located at Station 131 +46 and 903+48 should be
provided to the agencies for review prior to submitting the final plan.
Kimberly
Thomson
Isenhour
Digitally signed by
Kimberly Thomson
Isenhour
Date: 2023.04.04
15:23:29-04'00'
Kim Isenhour
Mitigation Project Manager
Wilmington District Regulatory Division
US Army Corps of Engineers